Conditional validation if checkbox selected laravel

You could do the following in this example:

public function rules(Request $request)
{
    if($request->has('updatepasswordcheck'))
    {
        $rules['oldpassword'] = 'required';
        $rules['newpassword'] = 'required';
        $rules['newpasswordconfirm'] = 'required';  
    }
    $rules['name'] = 'required|min:3';
    $rules['email'] = 'required|email';

    return $rules;
}

I'm using Laravel 5.5 and this code works fine, my scenario was if "Company Info" drop-down selected "Yes" then "Company Name" should be required.

Controller:

protected function validator(array $data)
{
   return Validator::make($data, [

      'company_name' => 'required_if:is_company,1',

   ]);
}

View:

<label class="control-label">Company Info</label>
<select id="is_company" class="form-control" name="is_company">
       <option value="0">No</option>
       <option value="1">Yes</option>
</select>


<label class="control-label">Company Name</label>
<input type="text" class="form-control" name="company_name">

More Detail

Ok I worked it out. I did this and it works:

public function rules()
{
        if($this->has('updatepasswordcheck'))
        {
            $rules['oldpassword'] = 'required';
            $rules['newpassword'] = 'required';
            $rules['newpasswordconfirm'] = 'required';  
        }
        $rules['name'] = 'required|min:3';
        $rules['email'] = 'required|email';

        return $rules;
}